2.9 million votes (2.7% of all votes cast in 2000) would not normally count for much, but in a closely balanced system they can wield enormous power. Folks in parliamentary systems understand that power and wield it well by forming coalitions with majority parties (cf. the religious parties in Israel).
The US lefties, however do not seem to get it that they do not have a parliamentary system, but a winner-takes all one - in which coalition forming is not an option. As a result, the minority parties invariably work in only one way - to diminish the power of their potential allies, thus abetting the victory of their potential enemies. Period.
It does not take rocket science to figure that out. Which makes me wonder whether insignificant minority groups putting their "candidates" for president are either (a) monumentally naïve or (b) acting as 'Trojan donkeys' in their own ideological rank and file (GP among liberals, Reform and Libertarians among conservatives).
I suspect that much of the animosity toward GP is triggered not by its supposed threat to the "Democratic machine" but by the monumental idiocy of the left politics in the US it exemplifies - as evidenced by an apparent belief that a bunch of way-in-the-left-field yahoos can win presidential election in a rather conservative country of 290 million.
PS. There are more effective ways of "sending a message" - lest one wishes to pursue this argument - than running a marginal candidate who is sure to attract a smaller share of votes than a margin of acceptable statistical error.
Wojtek